1. Field of the Invention
The present invention relates to a monitor system adapted for use in the control of the quantity of cut tobacco in cigarettes during the manufacture of the cigarettes.
2. Description of the Related Art
According to a cigarette manufacturing machine, as is generally known, cut tobacco is first fed onto a paper web traveling in one direction, and is then wrapped in the web, whereupon a continuous cigarette rod is formed. Thereafter, the formed cigarette rod is cut into individual cigarettes with a predetermined length.
Since each cigarette has opposite cut ends, the cut tobacco may possibly fall off from the cut ends.
In order to prevent the cut tobacco from falling off, the quantity of cut tobacco in the cut end portions of each cigarette is made larger than that in any other portion. Thus, the cigarette rod has high-density portions with an increased cut tobacco fill arranged at intervals equivalent to the length of each cigarette, and is cut in the center of each high-density portion to form individual cigarettes.
The cigarette manufacturing machine is provided with a pair of trimming disks for forming the high-density portions in the cigarette rod to be prepared. These trimming disks are arranged in rolling contact with each other right under an endless tobacco band, and are rotated in opposite directions. As the tobacco band travels, a layer of the cut tobacco formed on the lower surface of the band is fed toward the paper web, as is conventionally known.
Pockets are arranged at regular intervals on the peripheral edge portion of each trimming disk. While the trimming disks are rotating, each pocket of one disk and its corresponding pocket of the other disk cyclically meet each other right under the tobacco band.
The primary function of the trimming disks is to scrape off a surplus of the cut tobacco in the tobacco layer on the tobacco band by rotating, thereby adjusting the thickness of the cut tobacco layer on the tobacco band, that is, the tobacco supply from the tobacco band to the paper web.
If the pockets are formed on the trimming disks in the aforesaid manner, however, the thickness of the cut tobacco layer increases in proportion to the capacity of the pockets. Accordingly, the supply of the cut tobacco fed onto the paper web increases cyclically, so that the cigarette rod is formed having the high-density portions.
In order to cut the cigarette rod accurately in the center of each high-density portion, the rotational phases of the pockets of the trimming disks must be adjusted accurately to the cutting timing of cigarette rod.
If the peripheral speed of the trimming disks varies, however, the cigarette manufacturing machine is disabled from cutting the cigarette rod accurately in the center of each high-density portion, even though the traveling speed of the paper web or the cigarette rod is fixed.
As a result, the cut end portions of each cigarette are packed insufficiently with the cut tobacco, so that the quality of the cigarettes is poor.
It is necessary, therefore, to check the cigarette rod to see if it is cut accurately in the center of each high-density portion, during the operation of the cigarette manufacturing machine.
This inspection may be conducted by utilizing, for example, a density sensor for continuously detecting the filling density of the cut tobacco in the cigarette rod. Usually, this density sensor is used to adjust the thickness of the cut tobacco layer formed on the tobacco band, that is, the distance between each trimming disk and the tobacco band.
If an oscilloscope is connected to the density sensor through a measuring device at the time of the inspection, and if the cutting timing for the cigarette rod is applied to the input of the measuring device, however, the filling state of the cut tobacco in each cigarette can be displayed on the oscilloscope.
More specifically, the measuring device integrates detection signals from the density sensor for a given period of time, thereby continuously measuring the fill of the cut tobacco in, e.g., 20 equal divisions of each cigarette, and displays the resulting measurement data and the cutting timing superposed on the oscilloscope. Accordingly, an operator can determine, by a waveform displayed on the oscilloscope, whether or not the cigarette rod is cut accurately in the center of each high-density portion.
According to the measuring device described above, however, the measurement data for each cigarette are so few that it is hard to seize the filling state of the cut tobacco in detail.
The measuring device measures the data for the fill of the cut tobacco on the assumption that the traveling speed of the cigarette rod is fixed. If the speed of the rod is changed for, e.g., production control, therefore, the measurement data lack in accuracy. In this case, the measuring device should be adjusted according to the traveling speed of the cigarette rod. This adjustment is not easy, however, requiring expert knowledge.
Moreover, the measuring device and the oscilloscope must be connected to each other by means of an exclusive cable with every inspection, so that the inspection work is not easy after all.
In order to make a hard copy of the waveform displayed on the oscilloscope, furthermore, the picture on the scope must be photographed, thus complicating totalization of data for quality control.